Install one or a couple of 802.11 access point; requires one power adapter and one (or zero, if WDS is used) Ethernet cable per AP. Everyone in the office can then access the network using 802.11 adapters built into most laptops and in many desktops. Get up to 54 Mbps link speed.

Rip up your ceiling and route hundreds of cables to hundreds of IR transceivers there. Buy one IR modem for each computer, connect with more wires. Test the configuration. Get a few Mbps link speed.

Have you ever installed an access point infrastructure to cover more than a few users. Let me assure you, your WiFi plan would fail HARD on any sizeable installation - there is just too much overlap and too few channels to cover large areas well. Let alone halving your bandwidth straight up with WDS.

Transmitting the data through the air, you mean like WiFi and cell phones do all the time? Too bad we don't have a way to scramble the data in a way that makes its contents inaccessible unless someone has the "key"...

i agree, it's little different from wifi, but i don't understand why it's better than wifi? It doesn't sound cheaper to install. It's definitely not faster. It doesn't work through drywall. It doesn't sound like it's friendly to portable systems.

the TFA says it's better because it uses visible light rather than magnetic radio waves. It doesn't give any reasons why thats better. Though i imagine visible light is less prone to certain kinds of interference, its far more prone to the interference of walls.

This is a good point. You deserve an upmod. No signal interference is a good thing. And being able to limit the signal to one enclosed area instead of broadcasting to god knows where is also good. Security through obscurity.plus no interference... I like it.. An attacker would have to be in the room to have a go... provided your blinds were closed and the signal was, as has been pointed out, encrypted

i agree, it's little different from wifi, but i don't understand why it's better than wifi? It doesn't sound cheaper to install. It's definitely not faster. It doesn't work through drywall.

This is exactly why it's being researched, it doesn't work through drywall. Looking at the available wireless networks on my system right now, there are 10. And I live in your average American suburb. Ten years ago when I set up mine, it was the only one. What will there be in ten more years. But most are like mine,

When you start rolling out WiFi for a building, you quickly find that three non-overlapping channels is not enough to tesselate with properly, so in the end you have large shared broadcast segments and contrained bandwidth.

With the light fictures, they have alot of extra channels implicitly (unregulated spectrum), plus the directional nature of the light minimises overlap between stations. This alows for far greater bandwidth.

Transmitting the data through the air, you mean like WiFi and cell phones do all the time? Too bad we don't have a way to scramble the data in a way that makes its contents inaccessible unless someone has the "key"...

I assume you're suggesting they secure the data transmitted through the air scrambled with proven commercial protections like WEP [aircrack-ng.org], WPA-PSK [infoworld.com], or were you thinking they might secure it with a product more widely used, like GSM [wikipedia.org]?

Last month when I read the article about their system, they claimed it was a "highly secure solution." But they did did not reveal any technical details that said "we're using protocol x with algorithm y to secure communications." So for now, we know only that they claim their system i

Real enterprises treat it as a second class network, but all desktops are generally still on a wired network.

They also generally have you use an encrypted VPN even if you're on an internal WiFi.

The irony is that all but the most criminally negligent IT administrators would apply military-strength cryptography to their WiFi links, but allow data to traverse the wired connections in the clear, which means that the wireless link is substantially more secure!

One of the biggest vulnerabilities in any large office building is the wired network. It's trivial for an attacker dressed in a suit to simply walk in, sit down at an empty desk, plug in, and start doing packet captures. Switched networks provide minimal protection, thanks to DNS cache and ARP cache poisoning attacks and the like.

You'd be amazed at how ignorant typical IT administrators are of the risk. I've heard ridiculous things like:

"But you need to fill out a form to get network access!"- Only if I follow the rules. Nothing stops me from physically connecting.

"You need an AD account to connect to the network!"- They're thinking of network shares, but the exploitable vulnerabilities are at the IP network layer.

"Your computer is not a member of the domain, it can't connect!"- That's largely irrelevant, once you have a user account, practically everything is accessible even from a machine that's in an untrusted workgroup.

These aren't from rare isolated incidents either, I hear one of those three almost every time I sit down at a new customer as a consultant. System administrators live in a fantasy land of imagined security.

Because it's a security violation for any real enterprise. Forget Faraday, you're broadcasting, and accepting lightwave-carrier connections right through the air and the nearest window.

I can see how it would be a problem at night, but I seriously doubt you'ld have an easy time catching it in the daytime. It would be as easy or maybe even easier to watch people log on from a distance, with binoculars or a telescope.

I'm not even sure it would necessarily be a problem at night. I'm pretty sure these things would be programmed with maybe a 45-degree cone, and the client computers would be sending their signals back from down inside Cubicle Canyon. You might be able to get some reflection off the ceiling tiles and cubicle tops, but that's going to be a very weak signal.

Plus, there's no real indication of what frequency these use, but it seems to me that it'd be pretty simple to just put up a filter for that frequency on

So? Radio is light just a different color. I mean really you are just going to use the exact same types of solution for this as you would wifi. Encryption.The good thing is that since this is new you can take all the lessons learned from wifi and apply them to this tech.

So, security-wise, how is this LED transceiver different from a regular WiFi access point? You know they both use EM waves. Just different frequencies. It should be more secure because it is more directional and short-range. And you can always close the curtains if you need privacy. And there is no interference from a hundred other WiFi systems in your office building.

Maybe I'm just a bit dense but why would you need a 3 or even 10mbps solution like this in a professional setting when I can get better reliability and performance off of a cat3 cable and off the shelf NICs?

So this solution is somehow more secure than WIFI/RF although you don't mention how. Easier to setup but you would have to buy new adapters for each client and support them rather than the built in WIFI already present in pretty much all mobile devices. On top of it all provides less bandwidth then 802.11b. I admit I'm sold where do I sign?

I know it's a cool new toy I'm just saying I don't see how it is much better than WIFI. It's not like you won't have wires and controllers connecting all these lights and since you are going to have to replace your lights to have this work I don't see where the cost savings are going to be. As far as having to run fiber to each desktop maybe for a room of engineers but as far as the other 95% of the employees are going even with an entire floor running thin clients 1 or 10GB Ethernet and a good switch wil

This can use much higher output power, as it's the room lighting which you want to reach all areas of the room anyway. A drawback though is that the duty cycle has to be near 100%, otherwise the room lighting would dim. That has to cut into bandwidth.

A drawback though is that the duty cycle has to be near 100%, otherwise the room lighting would dim. That has to cut into bandwidth.

Use non-visible light spectrum and adjust your regular lights so that they doesn't bleed into the non-visible range. Just because it's included in the light fixture doesn't mean it has to provide your lighting.

It's true that IR was slow and cumbersome, but damn was it useful for small-file transfers, and most implementations were a LOT less cumbersome than, say, the simplest bluetooth.

There are several possible advantages to a concept like this.

First, light is a lot harder to intercept unless you can see it. Light cannot penetrate walls. For those applications where you are afraid of RF being intercepted by ne'er-do-wells, using light is pretty brilliant (OK, my only bad pun in this post, I promise. Maybe). A

Third, for those with some sort of sensitivity to RF (or perceived sensitivity), you're flooding them with, well, light. At much lower intensities than the light fixture is already putting out. If they're concerned about exposure to that, allow them to wear a fedora at work. Problem solved.

What about people with light sensitivities? Generally fluorescent lights aren't to bad when placed in pairs, but when you get odd numbers of light tubes and flickering, that does seem to cause trouble for some folks.

The blinking of fluorescent tubes is no faster than 120 Hz, as that's how often each zero crossing of the 60 Hz powerline frequency happens. I suspect the annoying visibly blinking fluorescent light fixtures have some flaw that makes them light up only on the half wave, at 60 Hz. 60 Hz is near, but certainly not beyond the upper limit of human perception. So yes, many people are going to be sensitive to certain fluorescent lights flickering.

you provided the best use cases i've seen for this tech, but aren't the people who whine about exposure to RF also the people who can detect the blinking of florescent lights? i think just as many people are going to complain about these lights giving them migranes and hypnotizing them.

Sounds very one-way, thus inappropriate for normal LAN use. On the other hand, there are quite a number of successful grocery store systems that use similar methods to change the value of smart price display tags. Although they do it by pulsing the normal fluorescent lights overnight (don't want to drive the customers mad). LED's could do the same thing faster, and would likely scale better as a result.

Ok, I am going to need you to go ahead and power cycle that modem for me. Oh, you don't know what that means, well unplug it, count to 30 in your head. Sir, in your head, not out loud. Ok, now plug it back in and call me back if you have any further issues. Thank you for calling

First was IBM Zurich 30 or so years ago with IR on the ceiling as a connection method

Then there was the IR profile for WiFi. 802.11b at 1Mbit actually has an optical option. However as there is nobody doing it any more so there is no standards compliant kit out there.

Otherwise it is a very cool idea for a number of applications. There are places where you just do not want radio for a variety of reasons. Light is much less likely to cause interference and is much easier to keep "contained" so it is not eavesdropped on.

But infra-red is light that's not normally visible... which makes me wonder if we had a proper capture device to convert radio to visual, could we actually see radio waves like we do with iR? If you put in a fog machine, will that let you see the edges of the broadcast wave?

I somehow doubt these systems use visible light or the headaches and epileptic shock rates will skyrocket from all the blinking.

Or mid-range wireless communication. Stations across town but within line of sight of each other could communicate with an IR laser at 1Mbps. That would be useful for establishing a (very local) wireless mesh without ISPs.

From having access points installed in a dusty warehouse ceiling, I found that the dust tends to collect on the top, with the bottom staying relatively clean. So the access points would be fine. Incorporate the transceiver in the top edge of a laptop's display and it would stay relatively clean.

As for the users, they tend to dust themselves. I suppose if they were government workers there might be a problem.

the newly formed company Fee@Ces inc. announced a breakthrough in encoding binary data in output stools."This is great !", an employee of the Sewer City company announced proudly, "Now when I want to convey messages to my colleagues, I simply visit the bathroom and the technology takes care of the rest. And, using our technology of a series of pipes, we can even use this to work from home.".Fee@Ces did mention that inputting data back to users is a bit harder, as a spokesman said: "Users will need to properly operate the machinery involved to read out the processed stool messages. Failure in doing so can give unexpected results.". It was unclear at the time of writing what the 'unexpected result' meant, as the spokesman had to quickly take care of an 'accident' he had at the bathroom himself.

Given the plethora of proven connectivity options out there, I can't envision a scenario where I would chose this implementation over others. From TFA they talk about saving energy with the LED lighting system, but couldn't you by a cheaper LED lighting control system without their "value added" data transmission tech added to the cost?

Given the plethora of proven connectivity options out there, I can't envision a scenario where I would chose this implementation over others. From TFA they talk about saving energy with the LED lighting system, but couldn't you by a cheaper LED lighting control system without their "value added" data transmission tech added to the cost?

Yes. However, so much of the cost of an LED system is in the LED's themselves, and so little is in the hardware that's running the driver, that adding extra functionality to the driver has marginal added cost to the overall package. Moreover, businesses and particularly government purchasing offices are *screaming* for managed light systems that they can remotely monitor and shut down per-unit. That means networking to the light, with control over whether it's on or off, is already included in such a des

I seem to recall when modems with lights were still in use, that a video tape of the flashing lights on the modem could be slowed down enough to read the stream of bits. Granted 3mb/s is a great deal faster than 56kb/s, but video technology is faster now, too.
I would presume there is encryption on both ends, but I see a small IR led "bug" left on top of a computer, cube wall, file cabinet, etc. serving as a middle man pickup of the stream while it is decoded on the other end.

If you can get physical access to the facility, they're screwed anyway. Your "bug" could be RJ-45 based and cover a lot more of the network.

I think the major point is that containing light is a lot easier than containing the current 802.11x frequency ranges. Light cannot penetrate walls. It can only penetrate air, glass, and other transparent or translucent surfaces.

Of course, electrons on copper are even more secure, assuming your hacker doesn't have building access. Anything that emits any form of rad

I seem to recall when modems with lights were still in use, that a video tape of the flashing lights on the modem could be slowed down enough to read the stream of bits. Granted 3mb/s is a great deal faster than 56kb/s, but video technology is faster now, too.
I would presume there is encryption on both ends, but I see a small IR led "bug" left on top of a computer, cube wall, file cabinet, etc. serving as a middle man pickup of the stream while it is decoded on the other end.

You would need a very special camera to catch such high-speed toggling of the LED. Normal video 24-30 frames per second. That's well below the 300 baud of even early modems and you need at least twice the switching frequency to get the data (Nyquist). At 3MB/s they would need to be encoding a lot of bits per switch to get in range of a video camera. Some specialized sensors can do 1 million frames per second but their buffers can only handle 100 frames at a time.

I could be mistaken here, but I think that's probably an urban legend. Even assuming that you were using a 300-baud modem that could show a nibble at a time on 4 parallel LEDs and that the LEDs were updated on every single bit, that would still be a potential flicker rate of 75Hz. That would be impossible to catch on any consumer-grade camera, although some specialized equipment could capture it. At 14.4kbps, it would be completely impossible with any video equipment that I'm aware of. At 56kbps forget abou

How is this any different from any other wireless network system out there? Encrypting the signal would work just as well with the bonus point that people don't accidentally stumble across the network and instead need to make an effort to actually physically locate and establish a line of sight to the station.

It's easy to see that any system requiring special light fixtures and modems for each PC will be far more expensive than simply setting up a wireless access point or two for each floor of a building. This wouldn't even just be a one-time cost, but would apply as part of regular maintenance - which is easier, to swap out a router, or to bring in contractors to replace all of a company's light fixtures?

A system like this could really only be practical where conventional wireless can't be used for some reason

You cant run a whole floor of 50 - 100 stations with "a wireless access point or two". Even limiting the number of users per AP, you find very quickly that there is not enough non-overlapping channels nor physical seperation to tesellate properly - let alone the interference from your neighbours - resulting in very poor bandwidth per user and a poor quality of service.

You could even use this for inter-building communication. Stick and transceiver on an outside wall, with the opposite building doing the same. For improved reliability increase the intensity and use a laser instead.

As other people have mentioned the technology is not that novel, but the fact they are actually try to move the technology forward is of interest, since there are scenarios where a more limited signal transmitting solution actually has it uses. Security being one of them. Sure any device in the r

But what about the people who say that fluorescent tube lights flicker at a frequency that gives them headaches etc? Oh boy there will be office workers complain these lights give them migraines, cancer, the lot.

Plus the occasional crazy telling us that the lights were speaking to him....

There's some truth to the fluorescent light complainers... old magnetic ballasts run the light at 60Hz, which can create noticeable flickering (you can see it easier if you look with the side of your vision).
Modern electronic ballasts run at very high (30khz+) frequencies and so don't have this problem.

Is there any risk of epilepsy [wikipedia.org]? I'm guessing there isn't (since it's way too fast), but the right combination of bits might be able to do it, though probably only if intentionally rigged. The point is that this technology makes that possible, perhaps also untraceable.

Because RF can go through walls and the whole point of visible band communication is privacy.

And short of a small overlap near doors, each room won't interfere with the room next door or the hallways.

3Mbps might be slow, but then again if you're sharing an 802.11g network with a few folks who are busy anyways but elsewhere in the location, it's gonna be that slow too, or slower. Or if you're in an apartment and can see 30 accesspoints from your location...